I'll bite...
Let's say that during his tenure in Europe, Jimmy Stewart's B-24 Liberator is shot down. Stewart manages to survive the crash only to be captured and placed in a prisoner of war camp. While in said camp, Stewart raises the morale of the men and an escape is planned and executed. Unfortunately, said escape fails and Stewart and his fellows in whatever German POW camp are forced to wait it out until the end of the war which isn't too long.
Stewart's time in the POW camp causes him to rethink his career upon returning stateside. As a result he decides to forego a return to Hollywood. Instead turning to business endeavours as well as continuing his work in the USAF. Eventually Stewart is approached by both political parties in order to run for political office. I could honestly see him go either way...
Say he wins an election to some post in the early 50's/late 60's and continues to do so building up some political experience. I could see him as a potential celebrity candidate in the 1960's....